Inorganic fibers are lightweight, easy to handle and excellent in heat resistance, and hence, they are used as a heat resisting sealing material, for example. On the other hand, in recent years, a problem has been pointed out that inorganic fibers are inhaled into a human body and the inhaled fibers invade the lung to cause disorders. Under such circumstances, bio-soluble inorganic fibers which do not cause or hardly cause disorders even if inhaled into a human body have been developed.
These bio-soluble inorganic fibers are processed into a shaped article such as a mat and a block, for example. The shaped articles are then applied to a furnace wall or the like after or while being adhered with each other by means of an adhesive. Since a shaped article formed of bio-soluble inorganic fibers is used at a temperature of 1100° C. or higher, an adhesive used for adhering these articles is required to have similar heat resistance.
Although various adhesives for inorganic materials have heretofore been developed (Patent Documents 1 to 5, for example), a few adhesives were developed for a shaped article formed of bio-soluble inorganic fibers.